Sidelink CSI report transmission method and conditions

Abstract

Certain aspects provide a method for wireless communication by a first wireless device. The method generally includes receiving one or more instances of a channel state information reference signal (CSI-RS), generating CSI based on one or more of the CSI-RS instances, determining timing for transmitting the CSI based at least in part on at least one condition involving the CSI-RS instances, and transmitting the CSI in accordance with the determined timing.

Description

[Technical field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to U.S. Application No. 17 / 020,707, filed September 14, 2020, which claims the benefit of and priority to U.S. Provisional Application No. 62 / 901,670, filed September 17, 2019, both of which are incorporated by reference in their entireties herein.

[0002] Aspects of the present disclosure relate to wireless communication, and more particularly, to techniques for managing channel state information (CSI) reporting between user equipment (UE) over a sidelink channel. [Background technology]

[0003]

[0003] Wireless communication systems have been widely deployed to provide various telecommunication services, such as telephone, video, data, messaging, broadcast, and the like. These wireless communication systems may employ multiple access technologies capable of supporting communication with multiple users by sharing available system resources (e.g., bandwidth, transmit power, and the like). Examples of such multiple access systems include Third Generation Partnership Project (3GPP®) Long Term Evolution (LTE®) systems, LTE-Advanced (LTE-A) systems, Code Division Multiple Access (CDMA) systems, Time Division Multiple Access (TDMA) systems, Frequency Division Multiple Access (FDMA) systems, Orthogonal Frequency Division Multiple Access (OFDMA) systems, Single Carrier Frequency Division Multiple Access (SC-FDMA) systems, and Time Division Synchronous Code Division Multiple Access (TD-SCDMA) systems, to name a few.

[0004]

[0004] These multiple access technologies are adopted in various telecommunication standards to provide a common protocol that allows different wireless devices to communicate on a city, national, regional, or even global scale. New Radio (e.g., 5G NR) is an example of an emerging telecommunication standard. NR is a set of extensions to the LTE mobile standard promulgated by 3GPP. NR is designed to better support mobile broadband Internet access by improving spectral efficiency, lowering costs, improving services, utilizing new spectrum, and better integrating with other open standards using OFDMA with cyclic prefix (CP) on the downlink (DL) and on the uplink (UL). For these purposes, NR supports beamforming, multiple-input multiple-output (MIMO) antenna technology, and carrier aggregation.

[0005]

[0005] However, as the demand for mobile broadband access continues to increase, further improvements to NR and LTE technologies are needed. Preferably, these improvements should be applicable to other multiple access technologies and the telecommunications standards that employ these technologies.

[0006]

[0006] Medium Access Control (MAC)-Control Element (MAC-CE) is a MAC layer communication structure that can be used for control command exchange between wireless nodes. For example, a base station may send a MAC CE to a user equipment (UE) to put the UE into a discontinuous reception (DRX) mode to reduce the UE's power consumption. The MAC-CE may be carried in a shared channel such as a physical downlink shared channel (PDSCH), a physical uplink shared channel (PUSCH), or a physical sidelink shared channel. The MAC-CE may also be used to communicate information that facilitates communication, such as information about buffer status and available power headroom. Summary of the Invention

[0007]

[0007] The systems, methods, and devices of the present disclosure each have several inventive aspects, no single inventive aspect being solely responsible for a desirable attribute.

[0008] One inventive aspect of the subject matter described in this disclosure may be implemented in an apparatus for wireless communication by a first wireless device. The apparatus generally includes a receiver configured to receive one or more instances of a channel state information reference signal (CSI-RS), at least one processor configured to generate CSI based on one or more of the CSI-RS instances and determine a timing for transmitting the CSI based at least in part on at least one condition involving the CSI-RS instances, and a transmitter configured to transmit the CSI according to the determined timing.

[0009] Another inventive aspect of the subject matter described in this disclosure may be implemented in an apparatus for wireless communication by a second wireless device. The apparatus generally includes a transmitter configured to transmit one or more instances of a channel state information reference signal (CSI-RS), a receiver configured to receive from the first wireless device a CSI generated based on one or more of the CSI-RS instances, and at least one processor configured to determine a link between the received CSI and the one or more instances of the CSI-RS instances based on at least one condition, and process the CSI according to the determined link.

[0010] Another inventive aspect of the subject matter described in this disclosure may be implemented in a method for wireless communication by a first wireless device. The method generally includes receiving one or more instances of a channel state information reference signal (CSI-RS), generating CSI based on one or more of the CSI-RS instances, determining a timing for transmitting the CSI based at least in part on at least one condition involving the CSI-RS instances, and transmitting the CSI according to the determined timing.

[0011] Another inventive aspect of the subject matter described in this disclosure may be implemented in a method for wireless communication by a second wireless device. The method generally includes transmitting one or more instances of a channel state information reference signal (CSI-RS), receiving from a first wireless device CSI generated based on one or more of the CSI-RS instances, determining a link between the received CSI and the one or more instances of the CSI-RS instances based on at least one condition, and processing the CSI according to the determined link.

[0012] Another inventive aspect of the subject matter described in this disclosure may be implemented in an apparatus for wireless communication by a first wireless device. The apparatus generally includes means for receiving one or more instances of a channel state information reference signal (CSI-RS), means for generating CSI based on one or more of the CSI-RS instances, means for determining a timing for transmitting the CSI based at least in part on at least one condition involving the CSI-RS instances, and means for transmitting the CSI according to the determined timing.

[0013] Another inventive aspect of the subject matter described in this disclosure may be implemented in an apparatus for wireless communication by a second wireless device. The apparatus generally includes means for transmitting one or more instances of a channel state information reference signal (CSI-RS), means for receiving from the first wireless device a CSI generated based on one or more of the CSI-RS instances, means for determining a link between the received CSI and the one or more instances of the CSI-RS instances based on at least one condition, and means for processing the CSI according to the determined link.

[0014]

[0014] Another inventive aspect of the subject matter described in the present disclosure may be implemented in a computer readable medium storing instructions for receiving one or more instances of a channel state information reference signal (CSI-RS), generating CSI based on one or more of the CSI-RS instances, determining a timing for transmitting the CSI based at least in part on at least one condition involving the CSI-RS instances, and transmitting the CSI in accordance with the determined timing.

[0015]

[0015] Another inventive aspect of the subject matter described in this disclosure may be implemented in a computer-readable medium storing instructions for transmitting one or more instances of a channel state information reference signal (CSI-RS); receiving from a first wireless device CSI generated based on one or more of the CSI-RS instances; determining a link between the received CSI and one or more of the CSI-RS instances based on at least one condition; and processing the CSI in accordance with the determined link.

[0016] Aspects of the present disclosure provide means for apparatus, processors, and computer-readable media for implementing the methods described herein.

[0017]

[0017] To the accomplishment of the foregoing and related ends, the one or more aspects comprise the features hereinafter fully described and particularly pointed out in the claims. The following description and the annexed drawings set forth in detail certain illustrative features of the one or more aspects. These features are indicative of but a few of the various ways in which the principles of the various aspects may be employed.

[0018]

[0018] Details of one or more implementations of the subject matter described in this disclosure are set forth in the accompanying drawings and the following description. However, the accompanying drawings only show some typical aspects of the disclosure, and therefore should not be considered as limiting the scope of the disclosure. Other features, aspects, and advantages will become apparent from the description, drawings, and claims. [Brief description of the drawings]

[0019] [Figure 1]

[0019] FIG. 1 illustrates an example wireless communication network in which certain aspects of the present disclosure may be implemented. [Diagram 2]

[0020] 1 is a block diagram illustrating an example base station (BS) and an example user equipment (UE), in accordance with certain aspects of the present disclosure. [Figure 3A]

[0021] FIG. 1 illustrates a diagrammatic representation of an exemplary vehicle-to-everything (V2X) system, in accordance with certain aspects of the present disclosure. [Figure 3B] FIG. 1 illustrates a diagrammatic representation of an example Vehicle-to-Everything (V2X) system, in accordance with certain aspects of the present disclosure. [Figure 4]

[0022] 4 illustrates example operations for wireless communication by a first wireless device in accordance with certain aspects of the present disclosure. [Diagram 5]

[0023] 5 illustrates example operations for wireless communication by a second wireless device, in accordance with certain aspects of the present disclosure. [Figure 6]

[0024] 1 is a call flow diagram illustrating an example process for wireless communication in accordance with certain aspects of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020]

[0025] For ease of understanding, wherever possible, the same reference numbers have been used to designate like elements that are common to each of the figures. It is contemplated that elements disclosed in one embodiment may be beneficially utilized on other embodiments without specific recitation.

[0021]

[0026] Aspects of the present disclosure provide apparatus, methods, processing systems, and computer-readable media for managing channel state information (CSI) reporting over a sidelink channel between two UEs. As described, the techniques presented herein enable CSI reporting to transmit UE options on how to generate CSI from multiple CSI-RS instances and / or when to report the generated CSI.

[0022]

[0027] The following description provides examples of sidelink CSI reporting techniques and does not limit the scope, applicability, or examples set forth in the claims. Changes may be made in the function and configuration of the elements described without departing from the scope of the disclosure. Various examples may omit, substitute, or add various procedures or components as appropriate. For example, the methods described may be performed in an order different from that described, and various steps may be added, omitted, or combined. Also, features described with respect to some examples may be combined in some other examples. For example, an apparatus may be implemented or a method may be practiced using any number of aspects described herein. Furthermore, the scope of the disclosure is intended to cover such apparatus or methods implemented using other structures, functions, or structures and functions in addition to or other than the various aspects of the disclosure described herein. It should be understood that any aspect of the disclosure disclosed herein may be embodied by one or more elements of a claim.

[0023]

[0028] Generally, any number of wireless networks may be deployed in a given geographic area. Each wireless network may support a particular radio access technology (RAT) and may operate on one or more frequencies. A RAT may also be referred to as a radio technology, air interface, etc. A frequency may also be referred to as a carrier, subcarrier, frequency channel, tone, subband, etc. Each frequency may support a single RAT in a given geographic area to avoid interference between wireless networks of different RATs. In some cases, 5G NR RAT networks may be deployed.

[0024]

[0029] FIG 1 illustrates an example wireless communication network 100 in which aspects of the present disclosure may be implemented. For example, as shown in FIG 1, UE 120a and / or UE 120b may include a Sidelink CSI Report Module (122a, 122b), which may be configured to perform operations 400 of FIG 4 and / or operations 500 of FIG 5 to manage sidelink CSI reporting as described herein.

[0025]

[0030] NR access (e.g., 5G NR) may support various wireless communication services, such as enhanced mobile broadband (eMBB) targeting wide bandwidth (e.g., 80 MHz or more), millimeter wave (mmWave) targeting high carrier frequencies (e.g., 25 GHz or more), massive machine type communication (MTC) targeting non-backward compatible MTC techniques, or mission-critical services targeting ultra-reliable low-latency communication (URLLC). These services may include latency and reliability requirements. These services may also have different transmission time intervals (TTIs) to meet their respective quality of service (QoS) requirements. Furthermore, these services may coexist in the same time domain resource (e.g., slot or subframe) or frequency domain resource (e.g., component carrier).

[0026]

[0031] As shown in FIG. 1, the wireless communication network 100 may include several base stations (BSs) 110a-z (each also referred to herein individually as BS 110 or collectively as BS 110) and other network entities. The BSs 110 may provide communication coverage for a particular geographic area, sometimes referred to as a "cell," which may be fixed or may move according to the location of the mobile BSs 110. In some examples, the BSs 110 may be interconnected to one another or to one or more other BSs or network nodes (not shown) in the wireless communication network 100 through various types of backhaul interfaces (e.g., direct physical connections, wireless connections, virtual networks, etc.) using any suitable transport network. In the example shown in FIG. 1, the BSs 110a, 110b, and 110c may be macro BSs for the macro cells 102a, 102b, and 102c, respectively. The BS 110x may be a pico BS for the pico cell 102x. BS 110y and 110z may be femto BSs for femto cells 102y and 102z, respectively. A BS may support one or more cells. BS 110 communicates with user equipment (UE) 120a-y (each also referred to herein individually as UE 120 or collectively as UE 120) in wireless communications network 100. UE 120 (e.g., 120x, 120y, etc.) may be dispersed throughout wireless communications network 100, and each UE 120 may be fixed or mobile.

[0027]

[0032] The wireless communication network 100 may also include a relay station, also referred to as a relay, etc. (e.g., relay station 110r), that receives transmissions of data or other information from an upstream station (e.g., BS 110a or UE 120r) and sends transmissions of data or other information to a downstream station (e.g., UE 120 or BS 110) or relays transmissions between UEs 120 to facilitate communication between the devices.

[0028]

[0033] A network controller 130 may couple to a set of BSs 110 and provide coordination and control for these BSs 110. The network controller 130 may communicate with the BSs 110 via a backhaul. The BSs 110 may also communicate with each other (e.g., directly or indirectly) via a wireless or wireline backhaul.

[0029]

[0034] FIG. 2 illustrates a block diagram of an example base station (BS) and an example user equipment (UE) in accordance with certain aspects of the present disclosure.

[0030]

[0035] At the BS 110, the transmit processor 220 may receive data from the data source 212 and control information from the controller / processor 240. The control information may be for a physical broadcast channel (PBCH), a physical control format indicator channel (PCFICH), a physical hybrid ARQ indicator channel (PHICH), a physical downlink control channel (PDCCH), a group common PDCCH (GC PDCCH), etc. The data may be for a physical downlink shared channel (PDSCH), etc. The processor 220 may process (e.g., encode and symbol map) the data and control information to obtain data symbols and control symbols, respectively. The transmit processor 220 may also generate reference symbols, such as for a primary synchronization signal (PSS), a secondary synchronization signal (SSS), and a cell-specific reference signal (CRS). A transmit (TX) multiple-input multiple-output (MIMO) processor 230 may perform spatial processing (e.g., precoding) on ​​the data symbols, control symbols, and / or reference symbols, if applicable, and may provide output symbol streams to modulators (MODs) 232a-t. Each modulator 232 may process a respective output symbol stream (e.g., for OFDM, etc.) to obtain an output sample stream. Each modulator may further process (e.g., convert to analog, amplify, filter, and upconvert) the output sample stream to obtain a downlink signal. The downlink signals from modulators 232a-t may be transmitted via antennas 234a-t, respectively.

[0031]

[0036] At the UE 120, the antennas 252a-252r may receive the downlink signals from the BS 110 and may provide received signals to demodulators in a transceiver (DEMODs) 254a-254r, respectively. Each demodulator 254 may condition (e.g., filter, amplify, downconvert, and digitize) a respective received signal to obtain input samples. Each demodulator may further process the input samples (e.g., for OFDM, etc.) to obtain received symbols. A MIMO detector 256 may obtain received symbols from all demodulators 254a-254r, perform MIMO detection on the received symbols if applicable, and provide detected symbols. A receive processor 258 may process (e.g., demodulate, deinterleave, and decode) the detected symbols and provide decoded data for the UE 120 to a data sink 260 and provide decoded control information to the controller / processor 280.

[0032]

[0037] On the uplink, at the UE 120, a transmit processor 264 may receive and process data from a data source 262 (e.g., for the Physical Uplink Shared Channel (PUSCH)) and control information from a controller / processor 280 (e.g., for the Physical Uplink Control Channel (PUCCH). The transmit processor 264 may also generate reference symbols for a reference signal (e.g., for a Sounding Reference Signal (SRS)). The symbols from the transmit processor 264 are transmitted to the TX The uplink signal may be precoded by a MIMO processor 266, further processed by demodulators 254a-254r in the transceiver (e.g., for SC-FDM, etc.), and transmitted to the BS 110. At the BS 110, the uplink signal from the UE 120 may be received by an antenna 234, processed by a modulator 232, detected by a MIMO detector 236 if applicable, and further processed by a receive processor 238 to obtain decoded data and control information sent by the UE 120. The receive processor 238 may provide the decoded data to a data sink 239 and the decoded control information to the controller / processor 240.

[0033]

[0038] The memories 242 and 282 may store data and program codes for the BS 110 and the UE 120, respectively. The scheduler 244 may schedule UEs for data transmission on the downlink or uplink.

[0034]

[0039] The controller / processor 280 or other processors and modules in the UE 120 may perform or direct the execution of processes for the techniques described herein. As shown in FIG. 2, the controller / processor 280 of the UE 120 has a sidelink CSI reporting module 122, which may be configured to configure / schedule CSI reporting for the UE 120 itself (in accordance with operation 400 of FIG. 4) and / or process sidelink CSI reporting from another UE (in accordance with operation 500 of FIG. 5). Although shown in a controller / processor, other components of the UE or BS may be used to perform the operations described herein.

[0035]

[0040] 3A and 3B illustrate diagrammatic representations of an example vehicle-to-everything (V2X) system in accordance with certain aspects of the present disclosure. For example, the vehicles illustrated in FIG. 3A and 3B may communicate over a sidelink channel and may perform sidelink CSI reporting as described herein.

[0036]

[0041] The V2X system provided in Figures 3A and 3B provides two complementary transmission modes: the first transmission mode illustrated as an example in Figure 3A involves direct communication (e.g., also referred to as sidelink communication) between participants in close proximity to each other in a local area; the second transmission mode illustrated as an example in Figure 3B involves network-over-network communication, which may be implemented via a Uu interface (e.g., a wireless communication interface between a radio access network (RAN) and a UE).

[0037]

[0042] Referring to FIG. 3A, a V2X system 300 (including, for example, vehicle to vehicle (V2V) communication) is shown with two vehicles 302, 304. A first transmission mode allows direct communication between different participants in a given geographic location. As shown, the vehicles can have a wireless communication link 306 (V2P) with a person (e.g., via a UE) through a PC5 interface. Communication between the vehicles 302 and 304 can also occur through a PC5 interface 308. Similarly, communication can occur from the vehicle 302 to other highway components (e.g., highway component 310), such as traffic signals or signs, through a PC5 interface 312 (V2I). For each communication link shown in FIG. 3A, bidirectional communication can occur between the elements, and thus each element can be a transmitter and receiver of information. The V2X system 300 can be a self-managed system implemented without assistance from a network entity. A self-managing system may enable improved spectrum efficiency, reduced costs, and increased reliability since no network service interruption occurs during handover operations for moving vehicles. V2X systems may be configured to operate in licensed or unlicensed spectrum, so that any vehicle with an on-board system may access common frequencies and share information. Such harmonized / common spectrum operation enables secure and reliable operation.

[0038]

[0043] 3B illustrates a V2X system 350 for communication between vehicles 352 and 354 through a network entity 356. These network communications may be through individual nodes, such as base stations (e.g., eNBs or gNBs), that send and receive information to and from the vehicles 352, 354 (e.g., relay information between the vehicles 352, 354). Network communications through vehicle-to-network (V2N) links 358 and 310 may be used for long-range communications between vehicles, such as, for example, to communicate the presence of a car accident some distance ahead along a road or highway. Other types of communications may be sent by the nodes to the vehicles, such as traffic flow conditions, road hazard warnings, environmental / weather reports, and service station availability, among other examples. Such data may be obtained from a cloud-based sharing service.

[0039]

[0044] In some situations, two or more subordinate entities (e.g., UEs) may communicate with each other using sidelink signals. As described above, V2V and V2X communications are examples of communications that may be transmitted over a sidelink. Other applications of sidelink communications may include public safety or service announcement communications, communications for proximity services, communications for UE-to-network relaying, device-to-device (D2D) communications, Internet of Things (IoE) communications, Internet of Things (IoT) communications, mission-critical mesh communications, among other suitable applications. In general, a sidelink may refer to a direct link between one subordinate entity (e.g., UE1) and another subordinate entity (e.g., UE2). Thus, a sidelink may be used by a scheduling entity (e.g., BS) to transmit and receive communications (also referred to herein as “sidelink signals”) that may be utilized for scheduling or control purposes but without relaying the communications through the scheduling entity. In some examples, sidelink signals may be communicated using a licensed spectrum (as opposed to wireless local area networks, which generally use unlicensed spectrum).

[0040]

[0045] Various sidelink channels may be used for sidelink communications, including the physical sidelink discovery channel (PSDCH), the physical sidelink control channel (PSCCH), the physical sidelink shared channel (PSSCH), and the physical sidelink feedback channel (PSFCH). The PSDCH may carry discovery expressions that enable nearby devices to discover each other. The PSCCH may carry control signaling, such as sidelink resource configurations and other parameters used for data transmission, and the PSSCH may carry data transmissions. The PSFCH may carry feedback, such as channel state information (CSI) related to the sidelink channel quality.

[0041] Example Methods and Conditions for Sidelink CSI Reporting

[0046] Aspects of the present disclosure provide apparatus, methods, processing systems, and computer-readable media for managing channel state information (CSI) reporting over a sidelink channel between two UEs. As described, the techniques presented herein enable CSI reporting to transmit UE options on how to generate CSI from multiple CSI-RS instances and / or when to report the generated CSI.

[0042]

[0047] CSI in NR includes various channel quality metrics such as channel quality indicator (CQI), precoding matrix indicator (PMI), CSI-RS resource indicator (CRI), Strongest Layer Indication (SLI), Rank Indication (RI), and L1-RSRP (for beam management).

[0043]

[0048] For V2X deployments as described with reference to Figures 3A and 3B, CSI reporting may be enabled and disabled by configuration. For flexibility, devices may be configured to report only a subset of the metrics for CSI reporting.

[0044]

[0049] For example, in the case of CSI collection for unicast transmission, CQI / RI reporting may be supported and in some cases may be reported jointly. However, for this purpose, PMI reporting may not be supported. Multi-rank PSSCH transmission may be supported with restrictions, e.g., up to two antenna ports.

[0045]

[0050] For sidelink CSI reporting, the CSI may be delivered using the PSSCH using the resource allocation procedure for data transmission. In such a case, the CSI may be multiplexed with the data or reported in a PSSCH containing only the CSI.

[0046]

[0051] Aspects of the present disclosure address various potential challenges presented when considering sidelink CSI reporting. For example, one potential challenge is how to link a CSI (report) transmission (from a receiver UE or Rx UE) to a CSI-RS transmission from a transmitter UE (the Tx UE that transmitted the CSI-RS). The PSSCH data transmission from the Tx UE and the PSSCH data transmission from the Rx UE may generally be unlinked and dependent on their respective traffic and transmission data rate requirements, which are not required to be the same between Tx / Rx UEs (or forward / reverse links).

[0047]

[0052] This potential challenge can be illustrated by considering an example in which a Tx UE sends two (re)transmissions, each with a CSI-RS, that are sent before a PSSCH transmission from the receiver UE that includes CSI feedback. In this scenario, it may not be clear how the Rx UE indicates the CSI-RS transmission instance for which this CSI was evaluated, or whether the Rx UE generated the CSI based on both CSI-RS instances (e.g., whether the reported metrics, such as CQI and / or RI, are taken as an average or some other function, such as min / max).

[0048]

[0053] Some scenarios may have more need for linkage between the Rx UE's CSI (report(s)) transmission and the Tx UE's CSI-RS transmission instances than others. For example, for some sidelink communications, the CSI may only be used to adapt to large-scale parameters (e.g., path loss, shadowing, rank observed over time, etc.) rather than adapting to small-scale variations (e.g., no PMI, no wideband CSI-RS, or CSI feedback per subband).

[0049]

[0054] Another potential challenge is how to multiplex (piggyback) the CSI report(s) onto the PSSCH transmission from the Rx UEs. It may be possible to include the CSI report(s) in one or more Medium Access Control (MAC) Control Elements (MAC CEs) or via some other form of multiplexing.

[0050]

[0055] Another potential challenge is how to deal with "stale" CSI, for example, when an Rx UE does not get an opportunity to transmit CSI feedback within a given (expiration) time (latency period). This may be the case, for example, when there is no active traffic (PSSCH) in the Rx UE to include CSI feedback. Furthermore, in some cases, a CSI-only PSSCH (without data bits) may not be supported) or some conditions for which a CSI-only PSSCH is triggered may not be met.

[0051]

[0056] The techniques presented herein may help address these challenges, for example, by enabling CSI reporting that transmits UE options on how to generate CSI from multiple CSI-RS instances and / or when to report the generated CSI.

[0052]

[0057] 4 illustrates example operations 400 for wireless communication by a first wireless device in accordance with certain aspects of the present disclosure. For example, the operations 400 may be performed by the CSI-report transmitting UE 120b of FIG. 1 (or UE B of FIG. 6) to send a sidelink CSI report to the CSI-RS transmitting UE 120a (or UE A of FIG. 6).

[0053]

[0058] The operations 400 begin, at 402, by receiving one or more instances of a channel state information reference signal (CSI-RS). At 404, the first wireless device generates CSI based on one or more of the CSI-RS instances. At 406, the first wireless device determines a timing for transmitting the CSI based at least in part on at least one condition involving the CSI-RS instance. At 408, the first wireless device transmits the CSI according to the determined timing.

[0054]

[0059] 5 illustrates example operations 500 for wireless communication by a second wireless device in accordance with certain aspects of the present disclosure. For example, the operations 500 may be performed by UE 120a of FIG. 1 (or UE B of FIG. 6) to process a sidelink CSI report sent from UE 120b (or UE B of FIG. 6) performing operations 400.

[0055]

[0060] The operations 500 begin, at 502, by transmitting one or more instances of a channel state information reference signal (CSI-RS). At 504, a second wireless device receives CSI generated based on one or more of the CSI-RS instances from the first wireless device. At 506, the second wireless device determines a link between the received CSI and one or more of the CSI-RS instances based on at least one condition. At 508, the second wireless device processes the CSI according to the determined link.

[0056]

[0061] The operations 400 of FIG. 4 and 500 of FIG. 5 may be understood with reference to the call flow diagram of FIG. 6, which illustrates UE B generating and transmitting a CSI report to CSI-RS transmitting UE A in accordance with aspects described herein.

[0057]

[0062] As shown, UE A transmits one or more instances of sidelink CSI-RS (at time instances t_1...t_n). As shown, UE_B generates CSI based on one or more of the CSI-RS instances.

[0058]

[0063] In some cases, UE B also determines a timing (e.g., time instance t_m) for transmitting the CSI based on one or more conditions involving the CSI-RS instance. UE B then transmits the CSI according to the determined timing (e.g., at t_m). As shown, the CSI report(s) may be included in a CSI-dedicated PSSCH or piggybacked on a data transmission at time instance t_m.

[0059]

[0064] As long as UE A knows the conditions on which UE B bases the CSI and / or timing, UE A may be able to determine the link between the received CSI report(s) and the CSI-RS instance(s) transmitted by UE A. This disclosure provides various proposals for transmitting sidelink CSI based on different conditions.

[0060]

[0065] According to a first proposal (proposal 1), a UE (UE A) sending CSI feedback may determine a time instance (t_m) for a transmitter UE based on one or more of the CSI-RS transmissions (e.g., received at t1, t2, ..tn). The content of the CSI may vary. In some cases, the CSI may include at least a CQI and an RI. In some cases, the CQI and the RI may always be reported together. In some cases, UE A may determine a time instance t_m for transmitting CSI feedback to UE B according to one or more determined CSI (or CSI-RS transmissions).

[0061]

[0066] In some cases, the Rx UE (UE A) may be further configured with a parameter (max_time_delay_CSI) indicating the maximum time delay between the reception of CSI-RS from the Tx UE (UE B) and the CSI transmission instance (t_m). In some cases, this max_time_delay_CSI may be part of the RRC (pre)configuration. In some cases, such a parameter (latency bound) may be maintained for each sidelink (PC5) RRC connection.

[0062]

[0067] In some cases, if the time between receipt of the CSI-RS (at time t_n) and a potential data transmission from the Rx UE (UE B) to the Tx UE (at time t_m) exceeds a configured max_time_delay_CSI (which may be considered a latency limit), the Rx UE will not include the CSI in its data transmission at t_m (e.g., the SL-CSI report may be considered canceled in this case).

[0063]

[0068] The UE may support various combinations of CSI-RS reporting configurations. In some cases, the UE may be configured to support various aperiodic CSI-RS configurations that are triggered (activated) in various manners, such as via an SCI with a CSI request field. In such cases, the sidelink CSI-RS may be transmitted in resource blocks used for the PSSCH associated with the CSI that triggers the report. The UE may be configured with a CSI reporting latency bound, as described above.

[0064]

[0069] In some cases, the Rx UE triggers a transmission of CSI piggybacked on a data channel (e.g., PSSCH) (e.g., transmission of CSI on PSSCH without SL-SCH) without the presence of data bits corresponding to CSI-RS reception from the Tx UE at time instance (t_n). In other words, the Rx UE may trigger a CSI-only transmission if a PSSCH transmission to the Tx UE is not made (or is not expected) until t_n+max_time_delay_CSI. In some cases, the Rx UE may trigger this transmission with enough time to account for processing. For example, the Rx UE may trigger a transmission at time (t_n+max_time_delay_CSI−X_slots), where X_slots is the time required to prepare a PSSCH transmission with CSI at the Rx UE (and may also account for the time required to reserve resources for the transmission).

[0065]

[0070] In some cases, when multiple CSI-RS instances are received in timeslots (t1, t2, ..tn) before the corresponding CSI feedback to be sent at time t_m, the UE may determine exactly how to calculate the CSI according to various options.

[0066]

[0071] For example, in some cases, the Rx UE may determine the CSI to feed back based only on the last CSI-RS received, In some cases, the CSI may be determined based on the CSI-RS within a time window, e.g., slots (t1, t2, ..tn) greater than t_m-max_time_delay_CSI.

[0067]

[0072] In some cases, one or more of the parameters (e.g., CQI and / or RI) included in the CSI feedback based on slots of multiple CSI-RS may be calculated as follows: In some cases, the CQI signaled in the CSI feedback may be calculated as an average CQI estimated over the CSI-RS instances. In some cases, the signaled CQI may be calculated as a minimum CQI estimated over the CSI-RS instances or as a maximum CQI estimated over the CSI-RS instances. In some cases, the signaled CQI may be calculated as a given statistic for the CQI estimated over the CSI-RS instances (as configured, e.g., the 75th percentile).

[0068]

[0073] In some cases, the RI signaled in the CSI feedback may be calculated as the minimum RI estimated over the CSI-RS instances or as the maximum RI estimated over the CSI-RS instances.

[0069]

[0074] In some cases, each individual CSI report (for a given CSI-RS transmission) may be sent individually (without combining). In such cases, the number of CSI reports may be indicated in the CSI transmission (e.g., an Rx UE may indicate n reports and provide CSI reports for t_1, t_2, .. t_n).

[0070]

[0075] In some cases, one or more CSI reports may be multiplexed with the PSSCH and transmitted as a MAC_CE. In such cases, each report may be carried in an individual MAC_CE, or a single MAC_CE may contain multiple (or all) of the reports.

[0071]

[0076] In some cases, one or more CSI reports may be bit-multiplexed with the PSSCH (similar to UCI on the PUSCH). In such cases, the Rx UE may send control information (e.g., over the SCI) indicating the presence of the report(s), the size of the report(s), and / or the number.

[0072]

[0077] In some cases, one or more CSI reports may be sent using resource element (RE) multiplexing rather than bit multiplexing. For example, the CSI report may be sent as a control channel (CCH) stage 2 control message and multiplexed with the PSSCH (assuming that control stage 2 is not bit multiplexed with the PSSCH but is RE multiplexed with the PSSCH as a separate physical channel). Stage 2 control generally refers to a two-part control protocol, for example, where a first stage message provides information regarding resource allocation and enables decoding of the second stage message. The second stage message may have a format (and may include information) specific to the type of message (e.g., unicast, broadcast, or groupcast).

[0073]

[0078] As described herein, a CSI-transmitting UE receiving multiple instances of CSI-RS may determine how to generate the CSI and / or when to send the CSI based on one or more conditions.

[0074]

[0079] The techniques described herein may be used for various wireless communication technologies, such as NR (e.g., 5G NR), 3GPP Long Term Evolution (LTE), LTE Advanced (LTE-A), Code Division Multiple Access (CDMA), Time Division Multiple Access (TDMA), Frequency Division Multiple Access (FDMA), Orthogonal Frequency Division Multiple Access (OFDMA), Single Carrier Frequency Division Multiple Access (SC-FDMA), Time Division Synchronous Code Division Multiple Access (TD-SCDMA), and other networks. The terms "network" and "system" are often used interchangeably. A CDMA network may implement a radio technology, such as Universal Terrestrial Radio Access (UTRA), cdma2000, etc. UTRA includes Wideband CDMA (WCDMA) and other variants of CDMA. cdma2000 covers IS-2000, IS-95 and IS-856 standards. A TDMA network may implement a radio technology, such as Global System for Mobile Communications (GSM). An OFDMA network may implement a radio technology such as NR (e.g., 5G RA), Evolved UTRA (E-UTRA), Ultra Mobile Broadband (UMB), IEEE 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, Flash-OFDMA, etc. UTRA and E-UTRA are parts of the Universal Mobile Telecommunications System (UMTS). LTE and LTE-A are releases of UMTS that use E-UTRA. UTRA, E-UTRA, UMTS, LTE, LTE-A and GSM are described in documents from an organization named "3rd Generation Partnership Project" (3GPP), and cdma2000 and UMB are described in documents from an organization named "3rd Generation Partnership Project 2" (3GPP2). NR is an emerging wireless communications technology under development.

[0075]

[0080] The techniques described herein may be used for the wireless networks and radio technologies mentioned above, as well as other wireless networks and radio technologies. For clarity, aspects may be described herein using terminology commonly associated with 3G, 4G, or 5G wireless technologies, although aspects of the present disclosure may be applied in other generation-based communication systems.

[0076]

[0081] In 3GPP, the term "cell" may refer to a coverage area of ​​a Node B (NB) or an NB subsystem serving this coverage area, depending on the context in which the term is used. In an NR system, the terms "cell" and BS, next generation Node B (gNB or gNode B), access point (AP), distributed unit (DU), carrier, or transmit reception point (TRP) may be used interchangeably. A BS may provide communication coverage for a macro cell, a pico cell, a femto cell, or other type of cell. A macro cell may cover a relatively large geographic area (e.g., a few kilometers in radius) and may allow unrestricted access by UEs with a service subscription. A pico cell may cover a relatively small geographic area and may allow unrestricted access by UEs with a service subscription. A femto cell may cover a relatively small geographic area (e.g., a home) and may allow restricted access by UEs with an association with the femto cell (e.g., UEs in a closed subscriber group (CSG), UEs for users in the home, etc.). A BS for a macro cell may be referred to as a macro BS. A BS for a pico cell may be referred to as a pico BS, and a BS for a femto cell may be referred to as a femto BS or a home BS.

[0077]

[0082] A UE may also be referred to as a mobile station, terminal, access terminal, subscriber unit, station, customer premises equipment (CPE), cellular phone, smartphone, personal digital assistant (PDA), wireless modem, wireless communication device, handheld device, laptop computer, cordless phone, wireless local loop (WLL) station, tablet computer, camera, gaming device, netbook, smartbook, ultrabook, appliance, medical device or equipment, biometric sensor / device, wearable device such as smart watch, smart clothing, smart glasses, smart wristband, smart jewelry (e.g., smart ring, smart bracelet, etc.), entertainment device (e.g., music device, video device, satellite radio, etc.), vehicle component or sensor, smart meter / sensor, industrial manufacturing equipment, global positioning system device, or any other suitable device configured to communicate over a wireless or wired medium. Some UEs may be considered machine type communication (MTC) devices or evolved MTC (eMTC) devices. MTC UEs and eMTC UEs include, for example, a robot, a drone, a remote device, a sensor, a meter, a monitor, a location tag, etc., that may communicate with a BS, another device (e.g., a remote device), or some other entity. A wireless node may provide, for example, connectivity for or to a network (e.g., a wide area network such as the Internet or a cellular network) via a wired or wireless communication link. Some UEs may be considered Internet of Things (IoT) devices, which may be Narrowband IoT (NB-IoT) devices.

[0078]

[0083] Some wireless networks (e.g., LTE) utilize orthogonal frequency division multiplexing (OFDM) on the downlink and single-carrier frequency division multiplexing (SC-FDM) on the uplink. OFDM and SC-FDM partition the system bandwidth into multiple (K) orthogonal subcarriers, also commonly referred to as tones, bins, etc. Each subcarrier may be modulated with data. In general, modulation symbols are sent in the frequency domain with OFDM and in the time domain with SC-FDM. The spacing between adjacent subcarriers may be fixed, and the total number of subcarriers (K) may be dependent on the system bandwidth. For example, the spacing of the subcarriers may be 15 kHz, and the minimum resource allocation (called a "resource block" (RB)) may be 12 subcarriers (or 180 kHz). Thus, the nominal fast Fourier transform (FFT) size may be equal to 128, 256, 512, 1024, or 2048 for system bandwidths of 1.25, 2.5, 5, 10, or 20 megahertz (MHz), respectively. The system bandwidth may also be partitioned into subbands. For example, a subband may cover 1.08 MHz (e.g., 6 RBs), and there may be 1, 2, 4, 8, or 16 subbands for 1.25, 2.5, 5, 10, or 20 MHz system bandwidths, respectively. In LTE, the basic transmission time interval (TTI) or packet duration is a 1 ms subframe.

[0079]

[0084] NR utilizes OFDM with CP on the uplink and downlink and may include support for half-duplex operation using TDD. In NR, a subframe is still 1 ms, but the basic TTI is called a slot. A subframe contains a variable number of slots (e.g., 1, 2, 4, 8, 16, ... slots) depending on the subcarrier spacing. An NR RB is 12 consecutive frequency subcarriers. NR may support a base subcarrier spacing of 15 KHz, and other subcarrier spacings may be defined relative to the base subcarrier spacing, e.g., 30 kHz, 60 kHz, 120 kHz, 240 kHz, etc. Symbol length and slot length scale with the subcarrier spacing. The CP length also depends on the subcarrier spacing. Beamforming may be supported and the beam direction may be dynamically configured. MIMO transmission with precoding may also be supported. In some examples, MIMO configurations in the DL may support up to eight transmit antennas with multi-layer DL transmission of up to eight streams and up to two streams per UE. In some examples, multi-layer transmission with up to two streams per UE may be supported. Multiple cell aggregation may be supported with up to eight serving cells.

[0080]

[0085] In some examples, access to the air interface may be scheduled. A scheduling entity (e.g., a BS) allocates resources for communication among some or all devices and equipment within its service area or cell. The scheduling entity may be responsible for scheduling, assigning, reconfiguring, and releasing resources for one or more subordinate entities. That is, for scheduled communication, the subordinate entities utilize resources allocated by the scheduling entity. A base station is not the only entity that may function as a scheduling entity. In some examples, a UE may function as a scheduling entity and schedule resources for one or more subordinate entities (e.g., one or more other UEs), and the other UEs may utilize resources scheduled by the UE for wireless communication. In some examples, a UE may function as a scheduling entity in a peer-to-peer (P2P) network or in a mesh network. In a mesh network example, the UEs may communicate directly with each other in addition to communicating with the scheduling entity.

[0081]

[0086] The term "determining" as used herein may encompass one or more of a wide variety of actions. For example, "determining" may include calculating, computing, processing, deriving, investigating, looking up (e.g., looking up in a table, database, or another data structure), assuming, etc. Also, "determining" may include receiving (e.g., receiving information), accessing (e.g., accessing data in a memory), etc. Also, "determining" may include resolving, selecting, choosing, establishing, etc.

[0082]

[0087] As used herein, "or" is used to be interpreted in an inclusive sense unless expressly stated otherwise. For example, "a or b" may include only a, only b, or a combination of a and b. As used herein, a phrase referring to "at least one of" or "one or more of" a list of items refers to any combination of those items, including single members. For example, "at least one of a, b, or c" is intended to encompass the possibilities of only a, only b, only c, a combination of a and b, a combination of a and c, a combination of b and c, and a combination of a, b, and c.

[0083]

[0088] The various example components, logic, logic blocks, modules, circuits, operations, and algorithmic processes described in connection with the implementations disclosed herein may be implemented as electronic hardware, firmware, software, or combinations of hardware, firmware, or software, including the structures disclosed herein and their structural equivalents. Interchangeability of hardware, firmware, and software has been described generally in terms of functionality and illustrated in the various example components, blocks, modules, circuits, and processes described above. Whether such functionality is implemented in hardware, firmware, or software depends on the particular application and design constraints imposed on the overall system.

[0084]

[0089] Various modifications to the implementations described in this disclosure may be readily apparent to those skilled in the art, and the general principles defined herein may be applied to other implementations without departing from the spirit or scope of the disclosure. Thus, the claims are not intended to be limited to the implementations shown herein, but are to be accorded the widest scope consistent with the disclosure and the principles and novel features disclosed herein.

[0085]

[0090] Moreover, various features described herein in the context of separate implementations may also be implemented in combination in a single implementation. Conversely, various features described with respect to a single implementation may also be implemented in multiple implementations separately or in any suitable subcombination. Thus, although features may be described above as working in a particular combination, and may even initially be claimed as such, one or more features from a claimed combination may in some cases be deleted from that combination, and the claimed combination may be directed to a subcombination, or a variation of the subcombination.

[0086]

[0091] Similarly, although operations are illustrated in the figures in a particular order, this should not be understood as requiring such operations to be performed in the particular order or sequence shown, or that all of the illustrated operations be performed, to achieve desirable results. Additionally, the figures may generally illustrate one or more exemplary processes in the form of a flow chart or diagram. However, other operations not shown may be incorporated into the generally illustrated exemplary process. For example, one or more additional operations may be performed before, after, simultaneously with, or between any of the illustrated operations. In some situations, multitasking and parallel processing may be advantageous. Moreover, it should be understood that the separation of various system components in the implementations described above should not be understood as requiring such separation in all implementations, and that the described program components and systems may generally be integrated together in a single software product or packaged in multiple software products. The invention as described in the claims of the original application is set forth below. [C1] An apparatus for wireless communication by a first wireless device, the apparatus comprising: a receiver configured to receive one or more instances of a channel state information reference signal (CSI-RS); at least one processor configured to generate CSI based on one or more of the CSI-RS instances and to determine a timing for transmitting the CSI based at least in part on at least one condition involving the CSI-RS instances; a transmitter configured to transmit the CSI in accordance with the determined timing. [C2] The apparatus of C1, wherein the transmitter is configured to transmit the CSI in a physical sidelink shared channel (PSSCH) transmission. [C3] The apparatus of C1, wherein the CSI comprises at least a channel quality indicator (CQI) and a rank indicator (RI). [C4] The apparatus of C1, wherein the at least one condition is based on a maximum time delay between reception of a CSI-RS instance and a CSI transmission instance. [C5] The apparatus of C4, wherein the receiver is further configured to receive radio resource control (RRC) signaling indicating a value of the maximum time delay. [C6] The apparatus of C4, wherein the transmitter is configured to transmit CSI for a given CSI-RS instance if a time between receipt of the CSI-RS instance and a potential data transmission from the first wireless device to a second wireless device is less than or equal to the maximum time delay. [C7] The apparatus of C4, wherein the first wireless device is configured to trigger transmission of CSI for the CSI-RS instance on a data channel without data bits if a time between reception of a given CSI-RS instance and a Physical Sidelink Shared Channel (PSSCH) transmission from the first wireless device to a second wireless device exceeds the maximum time delay. [C8] The apparatus of C7, wherein the first wireless device is configured to trigger the transmission of the CSI on the data channel in a time sufficient for the first wireless device to prepare the PSSCH transmission involving the CSI. [C9] generating CSI based on one or more of the CSI-RS instances, generating CSI for only the last received CSI-RS; or Generating CSI for one or more CSI-RS instances received within a window The apparatus described in C1, comprising: [C10] The apparatus of C9, wherein the window is based on a maximum time delay between reception of a CSI-RS instance and a CSI transmission instance. [C11] Generating CSI based on one or more of the CSI-RS instances includes generating a channel quality indicator (CQI): an average CQI estimated over said CSI-RS instances; a minimum CQI estimated over said CSI-RS instances; the maximum CQI estimated over said CSI-RS instances, or for a given statistic for CQI estimated across the CSI-RS instances. The apparatus of claim 1, further comprising: [C12] Generating CSI based on one or more of the CSI-RS instances includes: the minimum RI estimated over said CSI-RS instance, or The maximum RI estimated over the CSI-RS instance The apparatus of claim 1, further comprising: [C13] generating CSI based on one or more of the CSI-RS instances comprises generating individual CSI reports for a number of the CSI-RS instances; the transmitter is configured to transmit the individual CSI reports together with an indication of the number of CSI reports to be transmitted. The apparatus described in C1. [C14] The generating CSI based on one or more of the CSI-RS instances comprises generating individual CSI reports for a number of the CSI-RS instances; the transmitter is configured to transmit the number of CSI reports in at least one Medium Access Control (MAC) Control Element (MAC CE) multiplexed with a Physical Sidelink Shared Channel (PSSCH) transmission. The apparatus described in C1. [C15] Each CSI report is contained in an individual MAC CE, or a single MAC CE containing all of the CSI reports; The apparatus described in C14. [C16] Generating CSI based on one or more of the CSI-RS instances comprises generating one or more CSI reports for one or more of the CSI-RS instances; the transmitter is configured to transmit the one or more CSI reports multiplexed with a physical sidelink shared channel (PSSCH) transmission. The apparatus described in C1. [C17] The apparatus of C16, wherein the one or more CSI reports are bit multiplexed with the PSSCH. [C18] The apparatus of C16, wherein the one or more CSI reports are resource element (RE) multiplexed with the PSSCH. [C19] An apparatus for wireless communication by a second wireless device, the apparatus comprising: a transmitter configured to transmit one or more instances of a channel state information reference signal (CSI-RS); a receiver configured to receive, from a first wireless device, CSI generated based on one or more of the CSI-RS instances; at least one processor configured to determine a link between the received CSI and one or more of the CSI-RS instances based on at least one condition, and to process the CSI in accordance with the determined link; An apparatus comprising: [C20] The apparatus of C19, wherein the CSI is received in a physical sidelink shared channel (PSSCH) transmission. [C21] The apparatus of C19, wherein the CSI comprises at least a channel quality indicator (CQI) and a rank indicator (RI). [C22] The apparatus of C19, wherein the at least one condition is based on a maximum time delay between a transmission of a CSI-RS instance and a CSI transmission instance. [C23] The apparatus of C22, wherein the receiver is further configured to receive radio resource control (RRC) signaling indicating a value of the maximum time delay. [C24] The apparatus of C22, wherein the transmitter is configured to transmit CSI for a given CSI-RS instance if a time between receipt of the CSI-RS instance and a potential data transmission from the first wireless device to the second wireless device is less than or equal to the maximum time delay. [C25] The apparatus of C22, wherein the first wireless device is configured to trigger transmission of CSI for the CSI-RS instance on a data channel without data bits if a time between reception of a given CSI-RS instance and a Physical Sidelink Shared Channel (PSSCH) transmission from the first wireless device to the second wireless device exceeds the maximum time delay. [C26] The apparatus of C25, wherein the first wireless device is configured to trigger the transmission of the CSI on the data channel in a time sufficient for the first wireless device to prepare the PSSCH transmission involving the CSI. [C27] The at least one condition is that the first wireless device: generating CSI for only the last received CSI-RS; or Generating CSI for one or more CSI-RS instances received within a window The apparatus of claim 19, further comprising: [C28] The apparatus of C27, wherein the window is based on a maximum time delay between reception of a CSI-RS instance and a CSI transmission instance. [C29] The at least one condition may be such that the first wireless device: an average CQI estimated over said CSI-RS instances; a minimum CQI estimated over said CSI-RS instances; the maximum CQI estimated over said CSI-RS instances, or for a given statistic for CQI estimated across the CSI-RS instances. 20. The apparatus of claim 19, further comprising: [C30] The at least one condition may be such that the first wireless device sets a rank indicator (RI) as the minimum RI estimated over said CSI-RS instance, or The maximum RI estimated over the CSI-RS instance 20. The apparatus of claim 19, further comprising: [C31] The at least one condition is that the first wireless device: generating CSI based on one or more of the CSI-RS instances; and generating individual CSI reports for a number of the CSI-RS instances. transmitting the CSI and transmitting the individual CSI report together with an indication of the number of CSI reports to be transmitted. The apparatus of claim 19, further comprising: [C32] The at least one condition is that the first wireless device: generating CSI based on one or more of the CSI-RS instances; and generating individual CSI reports for a number of the CSI-RS instances. transmitting the CSI and transmitting the number of CSI reports in at least one Medium Access Control (MAC) Control Element (MAC CE) multiplexed with a Physical Sidelink Shared Channel (PSSCH) transmission. The apparatus of claim 19, further comprising: [C33] Each CSI report is contained in an individual MAC CE, or a single MAC CE containing all of the CSI reports; The apparatus described in C32. [C34] The at least one condition is that the first wireless device: generating CSI based on one or more of the CSI-RS instances; and generating one or more CSI reports for one or more of the CSI-RS instances. transmitting the CSI and transmitting the one or more CSI reports multiplexed with a physical sidelink shared channel (PSSCH) transmission. The apparatus of claim 19, further comprising: [C35] The apparatus of C34, wherein the one or more CSI reports are bit multiplexed with the PSSCH. [C36] The apparatus of C34, wherein the one or more CSI reports are resource element (RE) multiplexed with the PSSCH. [C37] A method for wireless communication by a first wireless device, comprising: Receiving one or more instances of a channel state information reference signal (CSI-RS); generating CSI based on one or more of the CSI-RS instances; determining a timing for transmitting the CSI based at least in part on at least one condition involving the CSI-RS instance; transmitting the CSI in accordance with the determined timing; A method comprising: [C38] A method for wireless communication by a second wireless device, comprising: transmitting one or more instances of a channel state information reference signal (CSI-RS); receiving, from a first wireless device, CSI generated based on one or more of the CSI-RS instances; determining a link between the received CSI and one or more of the CSI-RS instances based on at least one condition; and processing the CSI in accordance with the determined link. A method comprising: [C39] An apparatus for wireless communication by a first wireless device, the apparatus comprising: means for receiving one or more instances of a channel state information reference signal (CSI-RS); means for generating CSI based on one or more of the CSI-RS instances; means for determining a timing for transmitting the CSI based at least in part on at least one condition involving the CSI-RS instance; means for transmitting the CSI in accordance with the determined timing; An apparatus comprising: [C40] An apparatus for wireless communication by a second wireless device, the apparatus comprising: means for transmitting one or more instances of a channel state information reference signal (CSI-RS); means for receiving, from a first wireless device, CSI generated based on one or more of the CSI-RS instances; means for determining a link between the received CSI and one or more of the CSI-RS instances based on at least one condition; and means for processing the CSI in accordance with the determined link. An apparatus comprising: [C41] A computer-readable medium, comprising: Receiving one or more instances of a channel state information reference signal (CSI-RS); generating CSI based on one or more of the CSI-RS instances; determining a timing for transmitting the CSI based at least in part on at least one condition involving the CSI-RS instance; transmitting the CSI in accordance with the determined timing; A computer-readable medium having stored thereon instructions for performing the steps of: [C42] A computer-readable medium, comprising: transmitting one or more instances of a channel state information reference signal (CSI-RS); receiving, from a first wireless device, CSI generated based on one or more of the CSI-RS instances; determining a link between the received CSI and one or more of the CSI-RS instances based on at least one condition; processing the CSI in accordance with the determined links; A computer-readable medium having stored thereon instructions for performing the steps of:

Claims

1. An apparatus for wireless communication by a first wireless device, the apparatus comprising: a receiver configured to receive one or more instances of a channel state information reference signal (CSI-RS); generating one or more CSI reports for one or more of the CSI-RS instances; determining whether a time between receipt of a first CSI-RS instance of the one or more CSI-RS instances and a potential data transmission from the first wireless device is less than or equal to a maximum time delay; At least one processor configured to: transmitting a first CSI report of the one or more CSI reports for the first CSI-RS instance multiplexed with data in a Physical Sidelink Shared Channel (PSSCH) transmission if the time between the reception of the first CSI-RS instance and the potential data transmission is less than or equal to the maximum time delay; transmitting the first CSI report of the one or more CSI reports for the first CSI-RS instance without multiplexing the first CSI report with the data in the PSSCH transmission if the time between the reception of the first CSI-RS instance and the potential data transmission is greater than the maximum time delay; a transmitter configured to An apparatus comprising:

2. 10. The apparatus of claim 1, wherein the one or more CSI reports comprise at least a channel quality indicator (CQI) and a rank indicator (RI).

3. 10. The apparatus of claim 1, wherein the receiver is further configured to receive radio resource control (RRC) signaling indicating a value of the maximum time delay.

4. 2. The apparatus of claim 1, wherein the first wireless device is configured to trigger the transmission of the one or more CSI reports on the PSSCH transmission at a time when the first wireless device prepares the PSSCH transmission with the one or more CSI reports.

5. The at least one processor, generating the one or more CSI reports for only the most recently received CSI-RS; or generating the one or more CSI reports for the one or more CSI-RS instances received within a window 2. The apparatus of claim 1, configured to generate the one or more CSI reports for the one or more of the CSI-RS instances by:

6. The apparatus of claim 5, wherein the at least one processor is configured to generate the one or more CSI reports for the one or more of the CSI-RS instances by generating the one or more CSI reports for the one or more CSI-RS instances received within a window, the window being based on a maximum time delay between reception of a CSI-RS instance of the CSI-RS instance and a transmission instance of a corresponding CSI report of the one or more CSI reports.

7. The at least one processor further comprising: as an average CQI estimated over the one or more CSI-RS instances, as a minimum CQI estimated across the one or more CSI-RS instances, as a maximum CQI estimated across the one or more CSI-RS instances; or For a given statistic for a CQI estimated over the one or more CSI-RS instances, 13. The apparatus of claim 1, configured to generate the one or more CSI reports for the one or more of the CSI-RS instances by generating:

8. The at least one processor further comprising: a minimum RI estimated across the one or more CSI-RS instances; or A maximum RI estimated across the one or more CSI-RS instances.

13. The apparatus of claim 1 , configured to generate the one or more CSI reports for the one or more of the CSI-RS instances by generating:

9. The method of claim 8, wherein the at least one processor is configured to generate the one or more CSI reports for the one or more of the CSI-RS instances by generating an individual CSI report for each of the one or more CSI-RS instances; the transmitter is configured to transmit the individual CSI report together with an indication of a quantity of the individual CSI report to be transmitted.

2. The apparatus of claim 1.

10. The at least one processor is configured to generate the one or more CSI reports for the one or more of the CSI-RS instances by generating an individual CSI report for each of the one or more CSI-RS instances; the transmitter is configured to transmit the individual CSI report in at least one Media Access Control (MAC) Control Element (MAC CE) multiplexed with the data.

2. The apparatus of claim 1.

11. The method of claim 10, wherein each CSI report of the one or more CSI reports is included in an individual MAC CE; or a single MAC CE contains all of the CSI reports; 11. The apparatus of claim 10.

12. The device of claim 1, wherein if the time between the reception of the first CSI-RS instance and the potential data transmission is less than or equal to the maximum time delay, the one or more CSI reports are bit multiplexed with the data.

13. The device of claim 1, wherein the one or more CSI reports are resource element (RE) multiplexed with the data if the time between the reception of the first CSI-RS instance and the potential data transmission is less than or equal to the maximum time delay.

14. 1. A method for wireless communication by a first wireless device, comprising: Receiving one or more instances of a channel state information reference signal (CSI-RS); generating one or more CSI reports for one or more of the CSI-RS instances; determining whether a time between reception of a first CSI-RS instance of the one or more CSI-RS instances and a potential data transmission from the first wireless device is less than or equal to a maximum time delay; transmitting a first CSI report of the one or more CSI reports for the first CSI-RS instance multiplexed with data in a Physical Sidelink Shared Channel (PSSCH) transmission if the time between the reception of the first CSI-RS instance and the potential data transmission is less than or equal to the maximum time delay; transmitting a first CSI report of the one or more CSI reports for the first CSI-RS instance without multiplexing the first CSI report with the data in the PSSCH transmission if the time between the reception of the first CSI-RS instance and the potential data transmission is greater than the maximum time delay; A method comprising:

15. 16. An apparatus for wireless communication by a first wireless device, comprising: means for receiving one or more instances of a channel state information reference signal (CSI-RS); means for generating one or more CSI reports for one or more of the CSI-RS instances; means for determining whether a time between reception of a first CSI-RS instance of the one or more CSI-RS instances and a potential data transmission from the first wireless device to a second wireless device is less than or equal to a maximum time delay; means for transmitting a first CSI report of the one or more CSI reports for the first CSI-RS instance multiplexed with data in a Physical Sidelink Shared Channel (PSSCH) transmission if the time between the reception of the first CSI-RS instance and the potential data transmission is less than or equal to the maximum time delay; means for transmitting a first CSI report of the one or more CSI reports for the first CSI-RS instance without multiplexing the first CSI report with the data in the PSSCH transmission if the time between the reception of the first CSI-RS instance and the potential data transmission is greater than the maximum time delay; An apparatus comprising:

16. A non-transitory computer-readable medium storing instructions that, when executed by one or more processors, cause an apparatus to: Receiving one or more instances of a channel state information reference signal (CSI-RS); generating one or more CSI reports for one or more of the CSI-RS instances; determining whether a time between reception of a first CSI-RS instance of the one or more CSI-RS instances and a potential data transmission is less than or equal to a maximum time delay; transmitting a first CSI report of the one or more CSI reports for the first CSI-RS instance multiplexed with data in a Physical Sidelink Shared Channel (PSSCH) transmission if the time between the reception of the first CSI-RS instance and the potential data transmission is less than or equal to the maximum time delay; transmitting a first CSI report of the one or more CSI reports for the first CSI-RS instance without multiplexing the first CSI report with the data in the PSSCH transmission if the time between the reception of the first CSI-RS instance and the potential data transmission is greater than the maximum time delay; A non-transitory computer-readable medium for causing 17. The apparatus of claim 1, wherein the maximum time delay is based on a maximum time delay between reception of a CSI-RS instance among the CSI-RS instances and a transmission instance of a corresponding CSI report among the one or more CSI reports.

18. The method of claim 14, wherein the maximum time delay is based on a maximum time delay between reception of a CSI-RS instance among the CSI-RS instances and a transmission instance of a corresponding CSI report among the one or more CSI reports.

19. The apparatus of claim 15, wherein the maximum time delay is based on a maximum time delay between reception of a CSI-RS instance among the CSI-RS instances and a transmission instance of a corresponding CSI report among the one or more CSI reports.

20. The non-transitory computer-readable medium of claim 16, wherein the maximum time delay is based on a maximum time delay between reception of a CSI-RS instance among the CSI-RS instances and a transmission instance of a corresponding CSI report among the one or more CSI reports.

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